Dielectric and piezoelectric properties of Sr and La Co-doped PZT ceramics

PZT based piezoelectric ceramics doped with Sr2+ and La 3+, designated as PSLZT, were prepared by conventional processing techniques. The effect of the Zr/Ti ratio on the structural, dielectric and piezoelectric properties was investigated. XRD results showed that all PSLZT compositions had perovskite structure in which decreasing Zr/Ti ratio increased the tetragonality. The morphotropic phase boundary (MPB) appeared as a region extending from Zr/Ti ratio of 52/48 to 58/42. The PSLZT ceramic with a Zr/Ti ratio of 54/46 exhibited a remarkably high piezoelectric strain coefficient of 640 pC/N with attendant parameters of dielectric constant (1800), electromechanical coupling coefficient (0.56), mechanical quality factor (70), and Curie temperature (272°C). This soft PSLZT ceramic composition is a good candidate for electromechanical applications where quick switching and high operation temperature are needed.